The problem of compensating for the movement of a tow-fish carrying a narrow-beam sonar array is addressed. The aim is to steer the beam at a precise angle of incidence with respect to the sea bed and to maintain this by monitoring the pitch of the tow-fish and then adjusting the steered angle electronically in real time. In the application discussed here, the array is operated in conjunction with a hydrophone streamer deployed behind the tow-fish, but the problem is a general one applicable to any sonar platform.